1. Field of the Invention
The present invention relates generally to diving safety devices, and in particular, to an apparatus for preventing or minimizing decompression illness in a scuba diver.
2. Background and Related Art
Scuba divers are at risk for developing medical problems referred to as decompression illness (commonly known as the xe2x80x9cBendsxe2x80x9d), which is due to the formation of nitrogen bubbles in the tissues of the body. When these nitrogen bubbles form in the nervous system, problems such as numbness, weakness, paralysis, stroke and even death can result. Various theories exist to explain nitrogen bubble formation and elimination and these theories form the basis of diving decompression tables and algorithms used in dive computers. Several factors such as dive depth and duration are associated with increased nitrogen loading to the body and thus increased risk of decompression illness. Bubble formation can be minimized and bubble elimination can be optimized by slowing the ascent rate during decompression to allow nitrogen gas to be eliminated without forming clinically important tissue bubbles. Recommended ascent rates range from 30 to 60 feet per minute or even slower. Another method of minimizing nitrogen bubble formation and optimizing nitrogen bubble elimination includes the step of stopping at various depths prior to reaching the surface. Yet another effective strategy includes breathing 100% oxygen during a decompression stop, which minimizes nitrogen absorption, enhances nitrogen elimination and shortens the required decompression time.
Several devices for simplifying the ascent process exist in the art. One such device is disclosed in Shieh, U.S. Pat. No. 5,839,931. Shieh discloses a safety stop anchor including a buoy distantly connected to a scuba diver via a fixing rope. Before the scuba diver returns to the surface, the buoy helps the scuba diver to easily and relaxedly stay at the required safety decompression stop or stops to avoid nitrogen bubble formation. A buoyancy control valve is provided on the buoy so that heavy loads can be provided with neutral buoyancy and can therefore be more easily carried underwater and to the water surface. Thus, the apparatus of Shieh remains continuously connected to the scuba diver. Additionally, the apparatus does not provide for an alternative oxygen supply to further reduce nitrogen absorption.
Another prior art device is disclosed in Maffatone, U.S. Pat. No. 5,328,298. Maffatone discloses an ascent/decompression device for use in diving with an inflatable lift bag, which includes a pack for securing the ascent/decompression device on a diving harness worn by a scuba diver; a reel mounted for rotation to the pack and having a decompression line wound thereabout, the decompression line being connected to the lift bag; and a cable for securing the apparatus to a ship wreck on the sea floor. The apparatus utilizes an elaborate system to allow the scuba diver to follow the cable to the surface and then recover the cable once the scuba diver reaches the surface. As with the Shieh device, the Maffatone apparatus remains continuously connected to the scuba diver and does not provide for an alternative oxygen supply.
There continues to exist a need for an apparatus for preventing or minimizing decompression illness in a scuba diver that overcomes the shortcomings of the prior art.
The present invention is characterized in an apparatus for preventing or minimizing decompression illness in a scuba diver, consisting of a first safety bar, at least one first cable attached to the first safety bar, and an oxygen delivery system. The first cable supports the first safety bar at a predetermined depth. The oxygen delivery system consists of an oxygen tank, an oxygen delivery line, a manifold attached to the oxygen delivery line, and a plurality of regulators attached to the manifold. When the oxygen delivery system will be used by only one scuba diver, the oxygen delivery line can be connected directly to a single regulator without the manifold. The first cable and oxygen tank are attached to a float, which is either secured to a boat or platform via a tether line or anchored to the sea floor. In an alternative embodiment, the first cable is attached directly to a boat or platform, and an oxygen supply is provided on the boat or platform. In another alternative embodiment, the apparatus further includes a second safety bar connected to the first safety bar by at least one second cable, which supports the second safety bar at a predetermined depth below the depth of the first safety bar. In yet another alternative embodiment, the apparatus further includes a plurality of safety bars connected in series to the second safety bar by a plurality of cables, which support the plurality of safety bars at predetermined depths below the depth of the second safety bar.